Citrus tree named ‘Dity’

ABSTRACT

A new variety of mandarin citrus is described that is distinguished by fruit having few or no seeds, a mid-late fruit ripening period and orange-red fruit when fully ripe.

FIELD OF THE INVENTION

A new mandarin mandarin cultivar Citrus reticulata is described. The newvariety, designated ‘Dity’ is desirable to the consumer because of theorange-red color of its fruit and to the commercial grower because ofits appearance and mid-late fruit ripening.

BACKGROUND OF THE NEW PLANT

The present invention relates to a new and distinct variety of mandarincultivar Citrus reticulata developed by inventors Aliza Vardi, PinchasSpiegel-Roy, Ahuva Frydman-Shani, Avraham Elchanati and Hana Neumann inBet Dagan, Israel from a selection of plants grown from irradiated budwood of the cultivar ‘Edit’ (not patented).

Asexual reproduction by conventional bud grafting of the new variety atthe Agriculture Research Organization Volcani Center in Bet Dagan,Israel, has shown that the new characteristics are stabilized andpermanently fixed through successive propagation.

The objective in breeding the present new tree variety, assigned thedenomination ‘Dity’, was to obtain a mid-late season ripening mandarincitrus with few of no seeds (0-3) per fruit. In the spring of 1989,about 300 buds of the mandarin cultivar, ‘Edit’, were irradiated at theNahal Soreq Nuclear Center, Yavne, Israel, by exposure to 3.5 kh ofgamma radiation from a Co60 source. Troyer and sour orange nucellarrootstocks were bud grafted with the individual buds of irradiated‘Edit’ bud wood and labeled mV₁. Six to nine months after grafting theirradiated budwood, individual buds from the mV₁ plants were re-graftedon Troyer and Sour orange nucellar rootstocks to establish about 500 mV₂plants.

Field planting was established from container grown mV₂ plants in thespring of 1992 and 1993. The first fruits were observed inDecember-January 1995-1996 and a second observation made duringDecember-January of 1996-1997.

The selection ‘13/2/94’, was distinguished from ‘Edit’ in having fruitwith 0-3 seeds per fruit compared with 3-11 seeds for ‘Edit’ and inhaving low pollen fertility compared with ‘Edit’. Typically, 3% of thepollen grains of 13/2/94 were stained by acetocarmine compared with 80%staining for ‘Edit’.

SUMMARY OF THE INVENTION

Some characteristics of selection 13/2/94, designated ‘Dity’, comparedwith ‘Edit’ are shown in Table 1.

TABLE 1 Tree Fruit skin color Peelability Seeds/fruit Pollen fertility¹13/2/94 Orange 30B Easy 0-3  3% ‘Dity’ ‘Edit’ RHS30B Easy  3-11  80%¹Estimated by Acetocarmine staining

The following is a detailed description of the new mandarin citrusvariety based on observations made under typical Israeli groveconditions. Descriptions are based on observations of 3-4 year oldplants grown in Bet Dagan, Israel. Color designations are based oncomparisons determined from the R.H.S Colour Chart published by TheRoyal Horticultural Society.

The tree shape and fruit appearance are similar to that of ‘Edit’. Thetree is vigorous. Small thorns are usually present in the leafy part ofbranches. Main branches have an upright attitude and young shoots haveno anthocyanin coloration at the tip. The bearing of the tree is regularand the productivity is relatively high, about the same as for ‘Edit’.The canopy is moderately dense.

The bark of the young shoots is initially smooth and green graduallyturning into a smooth brown-gray.

The leaf blades are firm, without undulation and concave in crosssection. The leaves are similar to those of ‘Edit’ and are lancelolate,small to medium in size and without wings.

Th characteristics of the flowering and the flower parts are similar tothose of ‘Edit’. Flowering for both occurs at the end of March andbeginning of April in Bet Dagan, Israel. Both ‘Dity’ and ‘Edit’ produceabout the same number of flowers and flower drop for both occurs inJune. Terminal flower buds have no anthocyanin coloration. Flowers areborne singly and have an average number of stamens (about 20) withcomplete style development. Anther color is pale yellow to white. Pollenfertility is low as indicated by the observation that only 2% of thepollen grains were stained with acetocarmine in a test conducted at theAgricultural Research Organization, the Volcani Center, Israel, ascompared with about 80% for ‘Edit’ pollen grain.

The fruit is seedless or has few seeds, 0-3 seeds, even when optimalpollination conditions are employed. This compares with about 0-11 seedsper fruit in ‘Edit’. In other respects the fruit characteristics of‘Dity’ are in the range of the parent cv. ‘Edit’. The fruit shape isoblate and medium-sized. When 50 fruits were measured, the fruit had anaverage weight 94.6 grams, an average height 44.7 mm, and an averagediameter of 65 mm. The fruit has a moderately depressed stalk end. Thefruit surface is usually smooth with an orange color, RHS 30B, on TheRoyal Horticultural Society of London Colour Chart, and bears an averagenumber of conspicuous rind oil glands (30 per cm²). Fruit ripening doesnot differ from outside of the canopy to the inside, but the fruit colorof the outside canopy is a little brighter compared to the fruit colorof the inside canopy. There is no persistence of the style and theareola is not completely developed. A navel is absent or rare. The rindis thin and easy to peel.

The color of the albedo is white and the flesh is orange in color. Thefruit contains 9-11 segments and is very juicy. The external color ofthe seeds (when fresh) and dry is ivory. The internal seed coat is whiteand the cotyledons are white. Monoembryonic seeds are present. The seedsizes, shape and texture are similar to that of the parent ‘Edit’. Thefruit reaches maturity at the beginning of December to the end ofJanuary. The ripening of the fruit on the tree and within the fruit isuniform. Fruit remaining on the tree does not regreen and begins to losequality at the beginning of February. If there is a heavy crop and thefruits are not picked during the ripening season, the tree may becomealternate bearing (produces less fruit the following season).Pre-harvest drop of both developed and undeveloped fruit is similar tothat of the parent cv. ‘Edit’.

DESCRIPTION OF THE PHOTOGRAPHS

Sheet 1 shows the whole tree and canopy shape of the new variety.

Sheet 2 illustrates the exterior of the new fruit variety ‘Dity’ as wellas transverse midsections in a plane substantially perpendicular to theaxis.

DESCRIPTION OF THE NEW TREE

The following is a detailed description of the new mandarin citrusvariety ‘Dity’ based on observations made under typical Israeli groveconditions.

Tree:

Origin.—Irradiation of cv. ‘Edit’.

Classification.—Botanical: Citrus reticulata hybrid. Common: Mandarincitrus. Cultivar: ‘Dity’.

Shape.—Shape is rounded when pruned.

Thorns.—Small, 1-3 mm length.

Branching.—Upright.

Canopy.—Moderately dense.

Bark.—Immature: Smooth, green, RHS 139B. Mature: Smooth, greyed-green,RHS 197B.

Leaf.—Size: average 76 mm length, average 32 mm wide. Leaf blade: Firm,no undulation, concave cross section. Color: RHS 146A upper; RHS 146Clower. Shape: Lanceolate.

Petioles.—Average 8 mm length, average 1.5 mm diameter. Color: RHS 146A.

Habit.—Moderately vigorous.

Height.—2.3-3 m.

Trunk.—Average 37 cm in diameter at 20 cm above ground.

Disease resistance.—No particular suseptibility or resistance observed.

Winter hardiness.—Winter temperature in Bet Dagan, Israel averages 4-7degrees Centigrade.

Flower:

Petal color.—RHS 155B.

Petal number.—5.

Flowering period.—End of March to beginning of April (Israel).

Flower drop.—April.

Stamens.—Approximately 20 with complete style development.

Anther color.—Pale yellow to white, RHS 10C.

Pollen fertility.—Low, 3% by acetocarmine staining.

Anthocyanin coloration.—No coloration.

Fruit:

Shape.—Oblate.

Size.—Medium.

Weight.—94.6 g (average of 50 fruits).

Height.—44.7 mm.

Diameter.—Average 65 mm.

Surface color.—Orange RHS 30B.

Rind oil gland.—Moderately conspicuous (30 per cm²).

Style.—No persistence.

Navel.—Absent or rare; if present, they are very small and attached tothe peel.

Rind.—Thin and easy to peel.

Albedo.—White, RHS 12D.

Areola.—Incompletely developed.

Fruit segments.—9-11.

Color of flesh.—Orange, RHS 28B.

Time to maturity.—December-January (Israel).

Productivity.—60 kg/tree per season.

Fruit extract.—(Quality tested Jan. 20, 1997). Total soluble solids(TSS) 12.8%. Acid content: 1.57%. TSS/acid ratio 8.16. Flavor: Pleasant.

Seeds:

Color.—External: Ivory (dry, fresh) RHS 158A. Internal: White, RHS 164A.

Cotyledons.—Green-white RHS 157C.

Embryony.—Monoembryonic.

The tree and its fruit as described herein may vary somewhat in certaincharacteristics due to climatic and/or soil conditions under which thevariety is grown.

What is claimed is:
 1. A new and distinct variety of Citrus reticulatatree substantially as herein described and shown.